Mississippi State (18-7, 8-6 SEC) add to that halftime lead by building an 11-point lead in the second half, but Arkansas (9-16, 4-10) went on an 11-3 run to pull to within 3.
Mississippi State, on a 3-pointer by Michal Ignerski with the shot clock about to expire, built the lead back out to 6 points, 51-45, with 2:16 left in the game.
However, Arkansas scored the final 8 points of the game to seal the upset victory.
MSU had three shots at the basket the final 5 seconds of the game but all three were off the mark, including a layup at the buzzer.
Timmy Bowers led the Bulldogs in scoring with 24 points. Mario Austin, due to double and triple teams, was held to 5 points.
With a victory, the Bulldogs, due to Auburn's loss to Florida earlier in the day, would have clinched at least a tie for the Western Division title. The Bulldogs last divisional title was the 1995-96 season when they went to the Final Four.
The loss was the first for the Bulldogs in 37 games when they held an opponent under 65 points.
MSU next travels to Knoxville to face the Tennessee Volunteers Wednesday night before coming back home next Saturday to take on the Auburn Tigers in a game that will determine the winner of the Western Division title.
"Give (Arkansas) a lot of credit; they jumped up and made a lot of shots in the second half. They were 6-of-11 from the three-point line in the second half. We were up six, come out of a timeout and they hit an unbelievable shot from about 30 feet on Timmy Bowers to bring it to back to two.
"We didn't make any shots in the second half; we didn't score. They did a good job totally packing it in on Mario (Austin) and we couldn't get him the ball. And we couldn't make enough shots in the perimeter. We scored 21 points in the second half. You have to score more than that to win on the road."
Gene Swindoll is the publisher and owner of Gene's Page, the unofficial site for Mississippi State sports since October, 1996. He can be reached by email at firstname.lastname@example.org